Whichever colour interior you choose to go with make sure you choose nappa leather as its satin finish and looks classy. Stitching again make sure you go for double stitching style. Either colour combination will look great. Look at Waynes and Roland's 430s, both white, one with red the other with black, than see what does it for you. It's your car so it's what you are going to love. Both will look great mate.
Make sure you use a good trimmer and look at their work before you decide. The interior is as important as the rest of the car so put a lot of thought into the detail, colour scheme and you can't go wrong.
I took lots of photos and images from looking on the net and planned every part. It's like a big jigsaw, but worth the effort. Maybe some carbon fibre detail to finish it of!!